JP2019081829A - Photon up-conversion film and manufacturing method therefor - Google Patents

Abstract

To provide a novel solid-based up-conversion film high in luminous efficiency and a manufacturing method therefor.SOLUTION: The up-conversion film is a stretched film consisting of a composition containing at least an acceptor, a donor, and a matrix resin. The manufacturing method of the up-conversion film includes a process for stretching the composition containing at least the acceptor, the donor, and the matrix resin, in which the acceptor and the donor are water soluble, the matrix resin is a polyvinyl alcohol resin and the stretching is wet stretching in a boric acid solution.SELECTED DRAWING: None

Description

  The present invention relates to a photon up-conversion film that emits light at a shorter wavelength side than excitation light with respect to irradiation of excitation light, and a method of manufacturing the same.

  Photon up conversion (hereinafter sometimes simply referred to as “up conversion”) phenomenon that converts low energy light into high energy light is a special phenomenon that is generally not observed, and this technology can be put to practical use. Applications of light and applications different from that of light (solar cell field, photocatalyst field, bioimaging field, optical instrument field, etc.) can be expected.

A technique using triplet-triplet annihilation (TTA), which is caused by collision of molecules in a triplet state, is known as upconversion emission in organic materials.
In the upconversion using TTA, in a solution system in which a donor molecule and an acceptor molecule are dissolved in a solvent, energy is efficiently transferred due to the diffusion of the donor molecule and the acceptor molecule.
However, in the solution system, the field which can be put to practical use becomes limited, and the possibility of future application development can not be expanded.

Therefore, research and development of high efficiency upconversion luminescence in the solid state is also in progress.
However, in the solid state, diffusion of molecules hardly occurs. Therefore, it has been considered to increase the TTA probability by mixing molecules in a high concentration in the matrix to realize the upconversion phenomenon, but since diffusion is limited, it is hoped that the TTA probability will be greatly improved. Absent.

  Under the background as described above, a method of using a metal organic framework (MOF) complex having a precisely controlled crystal structure has also been proposed (see, for example, Patent Document 1).

International Publication No. 2016/204301

In the above-described method using MOF complexes, it has been reported that triplet energy is efficiently transferred between molecules due to the well-arranged molecules characteristic of these complexes to exhibit excellent up-conversion characteristics.
However, it is very difficult to produce moldings only with extremely minute MOF complexes. And when compounded with resin, the efficiency in the whole material will fall remarkably.
Then, this invention makes it a subject to consider the novel up conversion film of solid type with high luminous efficiency, and its manufacturing method, examined from a different viewpoint from the former.

The present invention is provided with the following composition in order to solve the above-mentioned subject.
That is, the upconversion film of the present invention is a stretched film composed of a composition containing at least an acceptor, a donor and a matrix resin.
Moreover, the method for producing an upconversion film of the present invention is a method for producing a photon upconversion film including the step of stretching a composition comprising at least an acceptor, a donor and a matrix resin, wherein the acceptor and the donor are water soluble The matrix resin is a polyvinyl alcohol-based resin, and the stretching is wet stretching in a boric acid aqueous solution.

  According to the present invention, transfer of triplet energy from a donor to an acceptor can be efficiently performed, and since the film can be provided as a solid film, it has high applicability and can be easily produced. There is also an advantage.

FIG. 1 shows a conceptual diagram of the mechanism of upconversion based on triplet-triplet annihilation. FIG. 2 is a graph showing the light emission characteristics of the films according to Examples 1 and 2 and Comparative Example 1. FIG. 3 is a graph showing the light emission characteristics of the films according to Example 3 and Comparative Example 2. FIG. 4 is a graph showing the light emission characteristics of the films according to Example 4 and Comparative Example 3. FIG. 5 is a graph showing the light emission characteristics of the films according to Example 5 and Comparative Example 4. FIG. 6 is a photograph showing the light emission state of the film according to Example 1. FIG. 7 is a photograph showing the light emission state of the film according to Example 4.

Mechanism of upconversion
The present invention utilizes the mechanism of upconversion based on triplet-triplet annihilation.
A conceptual diagram of this mechanism is shown in FIG.
As shown in FIG. 1, first, a donor absorbs incident light and gives an excited triplet state by intersystem crossing from an excited singlet state.
Thereafter, triplet-triplet energy transfer occurs from the donor to the acceptor to form an excited triplet state of the acceptor.
Next, due to diffusion / collision between the acceptors in the excitation triplet state, triplet-triplet annihilation occurs to generate an excitation singlet at a higher energy level, resulting in upconversion emission.
Such mechanisms themselves are known.

[Acceptor]
As apparent from the above mechanism, the acceptor receives a triplet-triplet energy transfer from the donor to form an excited triplet state, and the acceptors in the excited triplet state diffuse and collide with each other to form a triplet. -It causes triplet annihilation to generate excitation singlets at higher energy levels.
As such an acceptor, various compounds having a fused aromatic ring are known. For example, a compound having a naphthalene structure, an anthracene structure, a pyrene structure, a perylene structure, a tetracene structure, and a Bodipy structure (borondipyrromethene structure) is preferably mentioned.

  Among them, 9,10-diphenylanthracene represented by the following formula (1) and a substitution product thereof can be preferably adopted as the compound having an anthracene structure.

In the above formula (1), each of R _{1 to} R ₈ independently represents a hydrogen atom, a halogen atom, a cyano group, an amino group having an alkyl chain which may have 1 to 8 carbon atoms, and 1 carbon atom Alkyl group optionally having 12 to 12 branches, alkoxy group optionally having 1 to 12 carbon atoms, ethylene oxide chain represented by the following formula (2) or formula (3), or It represents an ammonium ion represented by the formula (4).

In the above formula (2), R ₉ represents an alkyl group having 1 to 3 carbon atoms, and n represents an integer of 1 to 4.

In the above formula (3), R ₁₀ and R ₁₁ each independently represent an alkyl group having 1 to 3 carbon atoms, and m and l each independently represent an integer of 1 to 4.

In the above formula (4), o represents an integer of 1 to 8, and R _{12 to} R ₁₅ each independently represent an alkyl group having 1 to 6 carbon atoms which may have a branch.

  Preferred compounds are specifically exemplified below.

An acceptor having a hydrophilic group such as an alkoxy group, an alkylene oxide chain (ethylene oxide chain, propylene oxide chain, etc.), a hydroxy group, a carboxyl group, an amino group, or an ammonium ion is preferably used in wet stretching since it has water solubility. Can.
The degree of water solubility can also be controlled by appropriately selecting the number of these functional groups, the chain length of the alkylene oxide chain, and the like.

〔donor〕
As is apparent from the above mechanism, the donor absorbs incident light, becomes an excited triplet state by intersystem crossing from an excited singlet state, and causes the acceptor to generate triplet-triplet energy transfer It is.
As such a donor, for example, one having a porphyrin structure, a phthalocyanine structure or a fullerene structure is preferable. Even if the structure has metal atoms such as Pt, Pd, Zn, Ru, Re, Ir, Os, Cu, Ni, Co, Cd, Au, Ag, Sn, Sb, Pb, P, As, etc. Good.

  Among them, a compound represented by the following general formula (5) having a porphyrin structure can be preferably employed.

In the above formula (5), each of R _{16 to} R ₂₃ independently represents a hydrogen atom, a halogen atom, a cyano group, an amino group having a branched alkyl chain having 1 to 8 carbon atoms, 1 carbon atom R 12 represents an alkyl group which may have a branch of 12 to 12, an alkoxy group which may have a branch having 1 to 12 carbon atoms, or an ethylene oxide chain represented by the following formula (6), and M represents a hydrogen atom, Represents platinum, palladium, zinc or copper, and Ar _{1 to} Ar ₄ each independently represent a hydrogen atom, a substituent represented by the following formula (7), a formula (8) or a formula (9), or It represents an ammonium ion represented by the formula (10).

In the above formula (6), R ₂₄ represents an alkyl group having 1 to 3 carbon atoms, and p represents an integer of 1 to 4.

In the above formula (9), R ₂₅ represents an alkyl group having 1 to 3 carbon atoms, and q represents an integer of 1 to 4.

In the above formula (10), r represents an integer of 1 to 8, and R _{26 to} R ₂₉ each independently represent an alkyl group having 1 to 6 carbon atoms which may have a branch.

  Preferred compounds are specifically exemplified below.

Donors having hydrophilic groups such as alkoxy groups, alkylene oxide chains (ethylene oxide chains, propylene oxide chains, etc.), hydroxy groups, carboxyl groups, amino groups, ammonium ions, etc. are suitably used in wet stretching because they have water solubility. Can.
The degree of water solubility can also be controlled by appropriately selecting the number of these functional groups, the chain length of the alkylene oxide chain, and the like.

[Matrix resin]
The matrix resin is used to provide the above-described donor and acceptor upconversion phosphor as a solid system, and a resin that can be filmed in a state including the donor and the acceptor and is stretchable is selected.
As such a matrix resin, polyvinyl alcohol resin, polyurethane resin, polystyrene resin, polymethyl (meth) acrylate resin, polycarbonate resin, epoxy resin and the like can be mentioned.
In the above, for example, in the case of a polyvinyl alcohol-based resin, the description “system” is intended to encompass, besides polyvinyl alcohol, a copolymer with other monomers such as polyvinyl alcohol-polyethylene copolymer and the like. .

〔Composition〕
The composition in the present invention contains at least the donor, the acceptor, and the matrix resin.
It is preferable to select a highly compatible combination of the donor and the acceptor and the matrix resin.
In particular, an embodiment in which a water-soluble compound and / or a salt thereof is used as a donor and an acceptor, and a water-soluble resin is combined as a matrix resin is preferable. Specific examples of these water-soluble materials have already been described above.
Use of such a water-soluble material enables wet stretching, which is preferable in order to obtain a high stretch ratio. The details regarding the stretching will be described later.

It is preferable that it is 0.0001-1 mass% with respect to the composition whole quantity as a mixture ratio of the donor in a composition.
As a mixture ratio of the acceptor in a composition, it is preferable that it is 0.01-20 mass% with respect to the composition whole quantity.
The blending proportion of the matrix resin in the composition is preferably 79 to 99.9% by mass with respect to the total amount of the composition.

[Stretch film]
The upconversion film according to the present invention is a stretched film comprising the above composition.

  The method of stretching is not particularly limited, and either fixed end stretching or free end stretching may be used, but free end stretching is preferable. The reason is as follows. In free end stretching in which the film end is not fixed, the film shrinks in a direction perpendicular to the stretching direction (that is, in the width direction). That is, since it is a method of stretching without suppressing shrinkage, between the main chains of the matrix resin is shrunk by stretching, and molecules are oriented in the stretching direction. As a result, the orientation function also increases as the stretching ratio increases.

The stretching method may be either uniaxial stretching or biaxial stretching. However, since the technical significance of the stretching in the present invention is to orient the molecules and promote the transfer of triplet energy, uniaxial stretching in which stretching is performed only in one direction is preferable.
Stretching may be performed in one step or in multiple steps.

The stretching method may be either wet stretching in which the film is stretched in a stretching bath or dry stretching in air, or both may be used in combination.
Wet stretching is preferred in that high magnification stretching is possible under relatively mild conditions.

As a draw ratio, 2.0 times or more is preferable with respect to original length, and 4.0 times or more is more preferable.
When drawing in multiple steps, the product of the draw ratio in each step is the final draw ratio of the drawn film.
Moreover, as an orientation function of a stretched film, for example, 0.05 or more is preferable, and 0.19 or more is more preferable. Although there is a fixed upper limit, generally speaking, the higher the orientation function, the higher the efficiency of triplet energy transfer accompanying molecular orientation is expected.

According to the study of the present inventor, a method of wet stretching using a water-soluble material as each material constituting the composition was advantageous for stretching at a high magnification.
In particular, when using a water-soluble compound as an acceptor and a donor, using a polyvinyl alcohol-based resin as a matrix resin, and performing stretching as wet stretching in a boric acid aqueous solution, high stretch ratio and orientation function are realized It turned out that it can be done. Thereby, high efficiency of triplet energy transfer from the donor to the acceptor can be realized.

  The thickness of the stretched film is not particularly limited, but is, for example, 20 to 40 μm.

  Hereinafter, the upconversion film and the method for producing the same according to the present invention will be described in detail using examples, but the present invention is not limited to these examples.

Synthesis Example 1: Synthesis of Acceptor A
The acceptor A was synthesized according to the following synthesis scheme.

Specifically, it is as follows.
<Synthesis of Compound 1>
Under nitrogen atmosphere, p-bromoanisole (1 g, 5.35 mmol) was poured into dry THF (20 ml) and stirred.
While the reaction solution was cooled to −78 ° C., 2.6 M n-butyllithium (2.3 ml, 5.89 mmol) was added dropwise and allowed to react for 1 hour while cooling.
2-Isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (1.19 ml, 5.89 mmol) was added and allowed to react overnight at room temperature.
Water was added to the reaction solution and extracted with ethyl acetate.
After drying under reduced pressure, 1.03 g of a clear liquid was obtained (yield 82%).
¹ H NMR (400 MHz, CDCl ₃ ) δ: 7.75 (d, J = 8.7 Hz, 2 H), 6.89 (d, J = 8.7 Hz, 2 H), 3.82 (s, 3 H), 1.31 (s, 12 H)

<Synthesis of Compound 2>
Compound 1 (1.03 g, 4.4 mmol) and 9,10-dibromoanthracene (0.652 g, 1.94 mmol) were added to dehydrated toluene (20 ml) and stirred under a nitrogen atmosphere.
Tetrakis (triphenylphosphine) palladium (0) (0.11 g, 0.095 mmol) and 2 M aqueous potassium carbonate solution (7 ml) were added dropwise to the reaction solution and allowed to react overnight.
Ethanol (5 ml) was added to the reaction solution and allowed to react further overnight. Water was added to the reaction solution, and extracted with ethyl acetate and chloroform.
Recrystallization with chloroform / methanol gave 0.736 g of pale yellow crystals (yield 97%).
¹ H NMR (400 MHz, CDCl ₃ ) δ: 7.74 (m, 4 H), 7.39 (d, J = 8.7 Hz, 4 H), 7.33 (m, 4 H), 7.14 (d, 7 J = 8.7 Hz, 4 H), 3.96 (s, 6 H)

<Synthesis of Compound 3>
Compound 2 (0.65 g, 1.66 mmol) was placed in dry dichloromethane (150 ml) and stirred under nitrogen atmosphere.
While cooling to −78 ° C., 1 M boron tribromide (8.5 ml, 8.5 mmol) was added dropwise, and after stirring for a while after completion of the addition, the mixture was allowed to react overnight at room temperature.
The solution was added to ice water and extracted with chloroform and ethyl acetate.
Drying under reduced pressure gave 0.533 g of a pale yellow solid (yield 88%).
¹ H NMR (400 MHz, DMSO) δ: 9.74 (s, 1 H), 7.65 (m, 2 H), 7. 39 (m, 2 H), 7.23 (d, J = 8.5 Hz, 2 H ), 7.03 (d, J = 8.5 Hz, 2 H)

<Synthesis of Compound 4>
Compound 3 (0.150 g, 0.414 mmol) and potassium carbonate (0.171 g, 0.124 mmol) were placed in N, N-dimethylformamide (DMF) (5 ml) and stirred at 80.degree.
To the reaction solution, ethyl bromovalerate (0.259 g, 1.24 mmol) was added dropwise and allowed to react overnight.
After completion of the reaction, the temperature was returned to room temperature, the reaction solution was poured into water, and the precipitated solid was filtered.
The resulting solid was recrystallized with ethyl acetate / hexane.
0.190 g of pale yellow crystals were obtained (yield 74%).
¹ H NMR (400 MHz, CDCl ₃ ) δ: 7.77 to 7.70 (m, 4 H), 7.37 (d, J = 8.7 Hz, 4 H), 7.36 to 7.30 (m, 4 H) ), 7.12 (d, J = 8.7 Hz, 4 H), 4.21-4.09 (m, 9 H), 2.46 (br t, J = 7.0 Hz, 4 H), 2.01- 1.84 (m, 8 H), 1.57 (s, 6 H), 1. 29 (t, J = 7.2 Hz, 6 H)

<Synthesis of Compound 5>
Compound 4 (0.150 g, 0.242 mmol) was stirred in methanol (10 ml).
Then, 1 M aqueous potassium hydroxide solution (5 ml) was added dropwise and allowed to react overnight at 80 ° C.
After completion of the reaction, the temperature was returned to room temperature, and the reaction solution was poured into water and acidified with dilute hydrochloric acid. The precipitated solid was filtered.
After drying under reduced pressure, 0.11 g of pale yellow crystals were obtained (yield 81%).
¹ H NMR (400 MHz, DMSO) δ: 12.40-11.81 (m, 2H), 7.67-7.61 (m, 4H), 7.43-7.39 (m, 4H), 7 .35 (d, J = 8.6 Hz, 4 H), 7. 20 (d, J = 8.7 Hz, 4 H), 4. 13 (t, J = 6.2 Hz, 4 H), 2. 36 (t, J = 7.3 Hz, 4 H), 1.95 to 1.62 (m, 8 H)

<Synthesis of acceptor A>
Compound 5 (0.100 g, 0.178 mmol) was taken in water (20 ml) and stirred.
Then, 10% aqueous solution of tetrabutylammonium hydroxide (0.83 ml) was added dropwise to the reaction solution.
After reacting for 2 hours at room temperature, it was filtered.
The filtrate was dried under reduced pressure to obtain 0.22 g of a pale yellow solid (yield 100%).
¹ H NMR (400 MHz, CD ₃ OD) δ: 7.70-7.64 (m, 4 H), 7.34-7.23 (m, 8 H), 7.15 (d, J = 8.6 Hz, 4H), 4.14 (t, J = 6.1 Hz, 4H), 3.24-3.16 (m, 16H), 2.30 (t, J = 7.2 Hz, 4H), 1.96- 1.82 (m, 8 H), 1.69-1.57 (m, 17 H), 1. 39 (sxt, J = 7.4 Hz, 17 H), 1.00 (t, J = 7.3 Hz, 24 H )

Synthesis Example 2: Synthesis of Acceptor B
The acceptor B was synthesized by the following synthesis scheme.

Specifically, it is as follows.
Compound 3 (0.100 g, 0.276 mmol) and t-butoxy sodium (0.0583 g, 0.607 mmol) were added to dehydrated ethanol (5 ml) under a nitrogen atmosphere and stirred at 80 ° C.
Then, 1,3-bis (2- (2- (2-methoxyethoxy) ethoxy) propan-2-yl-toluenesulfonate (0.327 g, 0.607 mmol) was added dropwise and allowed to react for 3 days.
After completion of the reaction, the reaction solution was returned to room temperature, and the reaction solution was poured into ethyl acetate and extracted with water, and then purified with a silica gel column (ethyl acetate: methanol = 50: 1).
0.100 g of pale yellow liquid was obtained (yield 33%).
¹ H NMR (400 MHz, CDCl ₃ ) δ: 7.77-7.71 (m, 4 H), 7.39-7.30 (m, 8 H), 7.21 (d, J = 8.8 Hz, 4 H ), 4.78-4.64 (m, 2H), 3.89-3.82 (m, 7H), 3.79-3.73 (m, 8H), 3.73-3.61 (m) , 32H), 3.58-3.50 (m, 8H), 3.36 (s, 12H)

Synthesis Example 3: Synthesis of Acceptor C
The acceptor C was synthesized by the following synthesis scheme.

Specifically, it is as follows.
Compound 3 (0.150 g, 0.414 mmol) and potassium carbonate (0.144 g, 1.04 mmol) were placed in N, N-dimethylformamide (DMF) (10 ml) and stirred at 80.degree.
To the reaction solution, 2- (2- (2-methoxyethoxy) ethoxy) ethyl 4-methylbenzenesulfonate (0.331 g, 1.04 mmol) was added dropwise and allowed to react overnight.
After completion of the reaction, the temperature was returned to room temperature, the reaction solution was poured into water, and the precipitated solid was filtered.
The resulting solid was recrystallized with ethyl acetate / hexane.
0.220 g of pale yellow crystals were obtained (yield 81%).
¹ H NMR (400 MHz, CDCl ₃ ) δ: 7.75-7. 70 (m, 4 H), 7. 37 (d, J = 8.6 Hz, 4 H), 7.36-7.30 (m, 5 H) ), 7.15 (d, J = 8.8 Hz, 4 H), 4.33-4.26 (m, 4 H), 4.01-3.93 (m, 4 H), 3.86-3.79 (M, 4H), 3.77-3.69 (m, 8H), 3.66-3.53 (m, 4H), 3.41 (s, 6H)

Synthesis Example 4: Synthesis of Donor A
The donor was synthesized by the following synthesis scheme.

Specifically, it is as follows.
<Synthesis of Compound 6>
Ethyl-5- (4-formylphenoxy) pentanoate (4.00 g, 16.0 mmol) and pyrrole (1.18 ml, 17.0 mmol) were placed in propionic acid (160 ml) and refluxed for 2 hours.
After completion of the reaction, the temperature was returned to room temperature, the reaction solution was poured into water, and the precipitated solid was filtered.
0.4 g of a purple solid was obtained (yield 8%).
¹ H NMR (400 MHz, CD ₂ Cl ₂ ) δ: 8.92 (s, 8 H), 8. 15 (d, J = 8.7 Hz, 8 H), 7.33 (d, J = 8.7 Hz, 8 H ), 4.32 (s, 8 H), 4.21 (d, J = 7.2 Hz, 8 H), 2.54 (t, J = 7.2 Hz, 8 H), 2.13-1.95 (m , 16H), 1.34 (t, J = 7.2 Hz, 12 H)

<Synthesis of Compound 7>
Compound 6 (0.0352 g, 0.0295 mmol) was placed in benzonitrile (40 ml) and dissolved.
Then, palladium chloride (0.0105 g, 0.0590 mmol) was added and refluxed for 5 hours.
After completion of the reaction, the temperature was returned to room temperature, and the solvent was removed under reduced pressure.
The obtained solid was recrystallized with ethyl acetate to obtain 0.03 g of red crystals. The obtained compound was used for the next reaction as it was.

<Synthesis of Donor A>
Compound 7 (0.0200 g, 0.0154 mmol) was placed in methanol / tetrahydrofuran (3 ml / 3 ml), 1 M aqueous potassium hydroxide solution (3 ml) was added, and the mixture was refluxed for 2 days.
It was then neutralized with 1 M hydrochloric acid to give a red solid.
The obtained solid was dried, poured into water, 10% by mass aqueous solution of tetramethylammonium hydroxide (0.485 ml) was added, and the mixture was stirred at room temperature for 1 hour.
After the reaction, the solvent was removed under reduced pressure and the obtained solid was washed with dichloromethane.
0.017 g of red solid was obtained (yield 74%).
¹ H NMR (400 MHz, CD ₃ OD) δ: 8.80 (s, 7 H), 7.99 (d, J = 8.6 Hz, 8 H), 7. 28 (d, J = 8.7 Hz, 8 H) , 4.81 (s, 192 H), 4.34 to 4.15 (m, 8 H), 2.37 to 2.28 (m, 8 H), 2.02 to 1.84 (m, 16 H)

Synthesis Example 5 Synthesis of Donor B
The donor was synthesized by the following synthesis scheme.

Specifically, it is as follows.
<Synthesis of Compound 8>
Tetrakis (4-carboxyphenyl) porphyrin (0.0700 g, 0.0885 mmol) and potassium carbonate (0.0979 g, 0.124 mmol) are placed in N, N-dimethylformamide (DMF) (15 ml) and stirred at 80 ° C. did.
To the reaction solution, 2- (2- (2-methoxyethoxy) ethoxy) ethyl 4-methylbenzenesulfonate (0.169 g, 0.531 mmol) was added dropwise and allowed to react for one day.
After completion of the reaction, the reaction solution is returned to room temperature, and the reaction solution is poured into ethyl acetate and extracted with water, and then washed with acetone and hexane to obtain 0.05 g of a purple solid (yield 41%).
¹ H NMR (400 MHz, (CD ₃ ) ₂ CO) δ: 9.27-8.62 (m, 8 H), 8.54-8. 42 (m, 8 H), 8.42-8.31 (m , 8H), 4.73 to 4.54 (m, 8H), 4.07 to 3.90 (m, 8H), 3.75 (s, 8H), 3.70 to 3.60 (m, 16H) ), 3.53 to 3.47 (m, 8H), 3.29 (s, 12H)

<Synthesis of Donor B>
Compound 8 (0.0300 g, 0.0218 mmol) was placed in benzonitrile (10 ml) and dissolved.
Then palladium chloride (0.00773 g, 0.0436 mmol) was added and refluxed overnight.
After completion of the reaction, the temperature was returned to room temperature, and the solvent was removed under reduced pressure.
The obtained solid was washed with acetone and hexane to obtain 0.025 g (yield 77%).
¹ H NMR (400 MHz, CD ₂ Cl ₂ ) δ: 8.74 (s, 8 H), 8. 36 (d, J = 7.5 Hz, 8 H), 8. 19 (d, J = 7.5 Hz, 8 H ), 4.54 (dd, J = 4.0, 5.5 Hz, 9 H), 3.93 to 3.78 (m, 8 H), 3.71 to 3.63 (m, 8 H), 3.62 -3.52 (m, 16H), 3.49-3.38 (m, 8 H), 3.25 (s, 12 H)

Example 1
0.001 parts by mass of donor A obtained in Synthesis Example 4 and 0.5 parts by mass of acceptor A obtained in Synthesis Example 1 were mixed with 100 parts by mass of a 10% by mass aqueous solution of polyvinyl alcohol, and mixed and stirred.
After degassing for 30 minutes, it was applied on a glass plate.
After drying at 90 ° C. for 15 minutes, the film was peeled from the glass plate to obtain an unstretched film.
The unstretched film was uniaxially stretched in the longitudinal direction while holding both ends in a 3% by mass aqueous solution of boric acid (stretching ratio: 4 times).
Then, the stretched film of Example 1 was obtained by drying at 60 degreeC for 5 minutes.

Example 2
A stretched film of Example 2 was obtained in the same manner as in Example 1 except that the draw ratio was doubled.

Comparative Example 1
The unstretched film before stretching in Example 1 was taken as Comparative Example 1.

[Example 3]
A stretched film of Example 3 was obtained in the same manner as Example 1, except that 0.5 part by mass of the acceptor A was used instead of 0.5 part by mass of the acceptor A.

Comparative Example 2
The unstretched film before stretching in Example 3 was taken as Comparative Example 2.

Example 4
Example 4 was carried out in the same manner as Example 1, except that 0.5 part by mass of the acceptor C obtained in Synthesis Example 3 was used instead of 0.5 part by mass of the acceptor A, and that the stretching ratio was 6 times. A stretched film of

Comparative Example 3
The unstretched film before stretching in Example 4 was taken as Comparative Example 3.

[Example 5]
Example 5 in the same manner as Example 1, except that 0.001 part by mass of donor B obtained in Synthesis Example 5 was used instead of 0.001 part by mass of donor A, and that the stretching ratio was 6 times. A stretched film of

Comparative Example 4
The unstretched film before stretching in Example 5 was taken as Comparative Example 4.

[Measurement of upconversion emission characteristics]
It is obtained by irradiating a laser beam from a light source (532 nm, CW laser, 260 mW / cm ² (in air)) manufactured by Laser Create, to each of the films of Examples 1 to 5 and Comparative Examples 1 to 4 obtained above. The luminescence was measured with a spectrometer (QE 65000, manufactured by Ocean Optics, Inc.). A notch filter (Edmond Optics Japan # 86-120) was placed in front of the spectroscope so that the incident light source (532 nm) did not directly enter the spectroscope.

[Measurement of degree of orientation]
Fourier transform infrared spectroscopy with an attachment for ATR measurement (ATR PRO 610 P-S (ZnSe prism), JASCO Corp.) with polarizing filter inserted into each film of Examples 1 to 5 and Comparative Examples 1 to 4 obtained above Using a photometer (FT / IR-4700, manufactured by Nippon Bunko Co., Ltd.), infrared absorption spectra were measured when the stretching direction was parallel to the infrared incident direction and when it was perpendicular. From the obtained spectrum, the orientation function was calculated from the intensity ratio in the direction perpendicular to the parallel direction at a peak intensity of 1325 cm ⁻¹ .

[Results and discussion]
The effect of stretching was verified by examining, for each stretching ratio, the ratio of the upconversion emission obtained from the acceptor in a wavelength range shorter than 532 nm of excitation light to the peak value of the phosphorescence emission of a long wavelength range donor.
The results of Examples 1 and 2 and Comparative Example 1 are summarized in FIG.
Moreover, the intensity | strength of 457 nm with respect to the 710 nm peak in each film of Example 1, 2 and the comparative example 1 was put together in the following table 1.

From the above results, it can be seen that upconversion emission hardly occurs in the unstretched state, but upconversion emission is more likely to occur by drawing. This tendency was more remarkable as the draw ratio was higher.
This result suggests that the up-conversion light emitting molecule is oriented by stretching, and that triplet energy transfer occurs efficiently.

The results of Example 3 and Comparative Example 2 are summarized in FIG.
Moreover, the intensity | strength of 450 nm with respect to the 710 nm peak in each film of Example 3 and Comparative Example 2 was put together in following Table 2.

The results of Example 4 and Comparative Example 3 are summarized in FIG.
Moreover, the intensity | strength of 446 nm with respect to the 710 nm peak in each film of Example 4 and Comparative Example 3 was put together in the following Table 3.

The results of Example 5 and Comparative Example 4 are summarized in FIG.
Moreover, the intensity | strength of 457 nm with respect to the 693 nm peak in each film of Example 5 and Comparative Example 4 was put together in the following Table 4.

  From the results of Examples 2 to 5 and Comparative Examples 2 to 4, it was confirmed that the upconversion emission characteristics were significantly improved by stretching even when the types of donors and acceptors were changed.

  Further, FIG. 6 shows a photograph of the upconversion light emission in the first embodiment, and FIG. 7 shows a photograph of the upconversion light emission in the fourth embodiment.

  As shown in FIGS. 6 and 7, it was confirmed that the irradiated part up-converted and emitted light at any position on the film. Large area light emission can be expected, and can be developed for various applications.

  The upconversion film of the present invention can be used, for example, as a film having a film thickness of about 20 to 40 μm, for various applications, and in particular, it stably emits upconversion light even when it is repeatedly irradiated with light in air. It is also suitable for use. Moreover, since the film is easy to process and inexpensive, it can be developed for various applications.

The present invention is provided with the following composition in order to solve the above-mentioned subject.
In other words, up-conversion film of the present invention, I oriented stretched film Der comprising the composition comprising at least a acceptor and donor and the matrix resin, the matrix resin is a polyvinyl alcohol resin.
The manufacturing method of upconversion film of the present invention is a method for producing a photon upconversion film comprising a step of stretching a composition comprising at least an acceptor and donor and the matrix resin, before Symbol matrix resin of polyvinyl alcohol It is a resin, and the stretching is a wet stretching in an aqueous boric acid solution.

The present invention is provided with the following composition in order to solve the above-mentioned subject.
In other words, up-conversion film of the present invention is an extension Shin film ing from a composition comprising at least a acceptor and donor and the matrix resin, the matrix resin Ri polyvinyl alcohol resin der, the matrix resin by stretching It is oriented .
The manufacturing method of upconversion film of the present invention is a method for producing a photon upconversion film comprising a step of stretching a composition comprising at least an acceptor and donor and the matrix resin, before Symbol matrix resin of polyvinyl alcohol It is a resin, and the stretching is a wet stretching in an aqueous boric acid solution.

Claims (9)

  The photon up conversion film which is a stretched film which consists of a composition which contains an acceptor, a donor, and matrix resin at least.   The photon upconversion film according to claim 1, wherein the acceptor is a compound having a naphthalene structure, an anthracene structure, a pyrene structure, a perylene structure, a tetracene structure or a Bodipy structure. The photon up conversion film according to claim 2, wherein the acceptor is a compound represented by the following formula (1).
In the above formula (1), each of R _{1 to} R ₈ independently represents a hydrogen atom, a halogen atom, a cyano group, an amino group having an alkyl chain which may have 1 to 8 carbon atoms, and 1 carbon atom Alkyl group optionally having 12 to 12 branches, alkoxy group optionally having 1 to 12 carbon atoms, ethylene oxide chain represented by the following formula (2) or formula (3), or It represents an ammonium ion represented by the formula (4).
In the above formula (2), R ₉ represents an alkyl group having 1 to 3 carbon atoms, and n represents an integer of 1 to 4.
In the above formula (3), R ₁₀ and R ₁₁ each independently represent an alkyl group having 1 to 3 carbon atoms, and m and l each independently represent an integer of 1 to 4.
In the above formula (4), o represents an integer of 1 to 8, and R _{12 to} R ₁₅ each independently represent an alkyl group having 1 to 6 carbon atoms which may have a branch.   The photon upconversion film according to any one of claims 1 to 3, wherein the donor is a compound having a porphyrin structure, a phthalocyanine structure or a fullerene structure. The photon up conversion film according to claim 4, wherein the donor is a compound represented by the following formula (5).
In the above formula (5), each of R _{16 to} R ₂₃ independently represents a hydrogen atom, a halogen atom, a cyano group, an amino group having a branched alkyl chain having 1 to 8 carbon atoms, 1 carbon atom R 12 represents an alkyl group which may have a branch of 12 to 12, an alkoxy group which may have a branch having 1 to 12 carbon atoms, or an ethylene oxide chain represented by the following formula (6), and M represents a hydrogen atom, Represents platinum, palladium, zinc or copper, and Ar _{1 to} Ar ₄ each independently represent a hydrogen atom, a substituent represented by the following formula (7), a formula (8) or a formula (9), or It represents an ammonium ion represented by the formula (10).
In the above formula (6), R ₂₄ represents an alkyl group having 1 to 3 carbon atoms, and p represents an integer of 1 to 4.
In the above formula (9), R ₂₅ represents an alkyl group having 1 to 3 carbon atoms, and q represents an integer of 1 to 4.
In the above formula (10), r represents an integer of 1 to 8, and R _{26 to} R ₂₉ each independently represent an alkyl group having 1 to 6 carbon atoms which may have a branch.   The photon up conversion film according to any one of claims 1 to 5, wherein the matrix resin is a polyvinyl alcohol resin, a polyurethane resin, a polystyrene resin, a polycarbonate resin or a poly (meth) acrylate resin.   The photon up conversion film according to claim 6, wherein the matrix resin is a polyvinyl alcohol resin.   A photon upconversion film according to any of the preceding claims, wherein the orientation function is greater than or equal to 0.05.   A method for producing a photon up-conversion film, comprising the step of stretching a composition containing at least an acceptor, a donor and a matrix resin, wherein the acceptor and the donor are water-soluble, and the matrix resin is a polyvinyl alcohol resin. The method for producing a photon up-conversion film, wherein the stretching is a wet stretching in an aqueous solution of boric acid.